Nakayama automorphism and applications
Nakayama automorphism is used to study group actions and Hopf algebra actions on Artin-Schelter regular algebras of global dimension three.
arXiv subjects
Publications and source records attributed to Jiafeng Lu.
Nakayama automorphism is used to study group actions and Hopf algebra actions on Artin-Schelter regular algebras of global dimension three.
The main purpose of this paper is to study a concrete example of $δ$-Koszul algebras, which is related to three questions raised by Green and Marcos in [3].
It is a small step toward the Koszul-type algebras. The piecewise-Koszul algebras are, in general, a new class of quadratic algebras but not the classical Koszul ones, simultaneously they agree with both the classical Koszul and higher Koszul algebras in special cases. We give a criteria theorem for a graded algebra $A$ to be piecewise-Koszul in terms of its Yoneda-Ext algebra $E(A)$, and show an $A_{\infty}$-structure on $E(A)$. Relations between Koszul algebras and piecewise-Koszul algebras are discussed. In particular, our results are related to the third question of Green-Marcos' [6].
In this paper, the criteria for minimal Horseshoe Lemma to be true are given via quasi-$δ$-Koszul modules, which are the nongraded version of $δ$-Koszul modules first introduced by Green and Marcos in 2005. Moreover, some applications of minimal Horseshoe Lemma are also given.